R'yleh? - edited

[Taqwus]

On extreme indy strength e.g. 9, try your hand at land before water. 90+ tritons can really, really chew up an undersea army quickly. Star Children can help a lot with indies; set way back, on 'fire'. You'll lose some to bodyguards or strong mages, especially if you try against non-indies, but they're cheap and can be produced on land at coastal castles.
I'd also make a fairly high dominion strength a priority, but it may be less important if you push onto land quickly and build numerous temples.
Astral/water gets you spell foci, starshine helmets, water bracelets (cheap +1 water; 2 water gets you astral clams), some nifty stuff all in all. Astral is powerful; precision attack spells, teleport, gateway, interesting remote summons...
A nature-3 mage will help a lot (nature 2 + thistle mace or moonvine bracelet, say), because that allows Cauldrons of Broth and illithids eat a lot. Nature 5, and cast Gift of Health, which will heal your feebleminded (Void Gate failure) starspawn priests. Also, your most powerful void summons, a Vastness, could benefit from a Gift of Reason because you have no commanders which can match its extreme mobility.
Remember that mind bLast always hits even in storms, or when it's dark, or even when you're blind! It's very long-range too; stay back, use Storms to shut down most flyers and hamper archery if possible, use your free hybrid troops to block and buy time if need be.